Windows 2000 uses IRQ steering to share interrupts on PCI components. IRQ steering uses IRQ9 to share interrupts. That is why you see so many components on that IRQ.
It is not likely that the shared IRQ is causing your problems. The steering table is assembled in hardware and delivered to the operating system. In most circumstances, the system does a correct job of sorting through the various components on the PCI bus.
If you want to check for resource issues associated with IRQ steering, open the Device Manager (DEVMGMT.MSC) and use the View menu to Sort Resources by Type. If you see a question mark or exclamation point next to one of the IRQ9 resources, you might try moving the device to a different PCI slot. IRQ steering cannot be disabled on an ACPI system.
This was first published in May 2001